What are the instructions for using a lidocaine (local anesthetic) patch to manage shingles pain?

Lidocaine Patch Instructions for Shingles Pain Management

Apply lidocaine 5% patches to intact skin (avoiding blisters and open lesions) for 12 hours on, then 12 hours off, using up to 3-4 patches simultaneously to cover the painful area, which provides effective pain relief for both acute herpes zoster and postherpetic neuralgia. 1, 2

Application Protocol

Patch Placement and Duration

• Apply patches only to intact skin areas without blisters or open wounds to avoid systemic absorption and potential toxicity 1, 2
• Use the standard 12-hour on, 12-hour off schedule regardless of how many patches you apply 1
• Up to 3-4 patches may be applied simultaneously to cover larger painful areas, depending on the size of the affected dermatome 3, 1
• Remove all patches after 12 hours and allow a complete 12-hour patch-free interval before reapplying 1

Timing Considerations

• Lidocaine patches can be used during acute herpes zoster (within 4 weeks of onset) when applied to intact skin portions, providing significant pain relief during both rest and movement 2
• For acute shingles, patches applied twice daily for 2 consecutive days demonstrated mean pain reduction of 14.7 points at rest and 10.4 points during movement compared to placebo 2
• Patches are also effective for postherpetic neuralgia (pain persisting beyond one month after rash onset) 4, 5

Safety Monitoring and Precautions

What to Watch For

• Monitor for signs of systemic absorption including dizziness, confusion, and bradycardia, particularly when using multiple patches 3, 1
• Perform periodic skin checks for irritation, rash, or sensitization at application sites 3, 1
• Blood lidocaine concentrations remain within safe ranges (59-431 ng/ml) with up to 4 patches in 24 hours 5

Critical Contraindications

• Do not apply to broken, blistered, or inflamed skin as this increases systemic absorption risk 3, 1, 2
• Avoid use in patients with advanced liver failure 3, 1
• Do not use if there is known hypersensitivity to amide anesthetics 6, 1
• Never apply lidocaine patches within 4 hours of other local anesthetic interventions (nerve blocks, epidural injections, or other topical lidocaine products) to prevent cumulative toxicity 7, 3, 1

Common Pitfalls to Avoid

• Never exceed the 12-hour application period, even if pain persists, as this increases toxicity risk without additional benefit 1
• Do not use multiple lidocaine-containing products simultaneously (e.g., cream and patch together) 6, 1
• Avoid applying excessive heat over patch areas (heating pads, hot water bottles) as this increases systemic absorption 3, 1
• If using intravenous lidocaine therapy for any reason, remove topical patches before starting the IV infusion 3

Alternative and Adjunctive Approaches

For Inadequate Relief

• If patches alone provide insufficient pain relief, consider adding systemic agents in the following order: gabapentin or pregabalin first, then tricyclic antidepressants (amitriptyline, nortriptyline), and lastly opioids (tramadol, oxycodone) 4
• For acute herpes zoster, ensure antiviral therapy (acyclovir, valacyclovir, or famciclovir) is started within 72 hours of rash onset to reduce acute pain severity and PHN risk 4
• Early initiation of gabapentin or amitriptyline after acute herpes zoster onset may prevent PHN development in high-risk patients 4

Topical Alternatives

• Capsaicin cream may be considered as an alternative topical agent, though it requires multiple applications and has an initial burning sensation 3
• Higher concentration lidocaine ointments (9% lidocaine base in petrolatum) have shown efficacy but require careful monitoring 8